Something very strange and mysterious was going on in Sesemann's house. Every morning, when the servants went downstairs, they found the front door wide open. During the first few days that this happened, every room and corner was searched in great alarm to see if anything had been stolen, but not a thing in the house had been touched. The door was doubly locked at night, and for further security the wooden bar was fastened across it; but it was no good – next morning the door again stood open. One servant even claimed he had seen a white figure standing at the top of the steps and then all in a minute it disappeared.
Mr. Sesemann told his old friend, a doctor, what had happened in his house. That evening they decided to wait for the ghost. One o'clock struck. There was not a sound. Suddenly the doctor lifted his finger. "Hush! Don't you hear something?" They both listened, and they distinctly heard the bar softly pushed aside and then the key turned in the lock and the door opened. They stepped into the hall.
"Who is there?" thundered the doctor in a voice that echoed through the hall, as the two men advanced with lights and weapons towards the figure. It turned and gave a low cry. There stood Heidi, with bare feet, staring with wild eyes and trembling from head to foot. The two men looked at one another in surprise. "Child, why did you come down here?" said Sesemann. White with terror, and hardly able to make her voice heard, Heidi answered, "I don't know." The doctor gently took the child by the hand upstairs.
Then the doctor sat down besides her and asked her some questions in a kind voice. Later he went downstairs. "Sesemann," he said, "let me first tell you that the child is a sleep-walker; secondly, the child is consumed with homesickness. Something must be done at once."